Document WO2010/014001 discloses a breast scanner comprising an object positioning device, which comprises a frame supporting at least two positioning members—embodied as positioning plates—defining between them an imaging space for a breast to be imaged of a subject and allowing for insertion of the breast to be imaged in an intended insertion direction of the breast to be imaged, wherein at least one of the positioning members is movably mounted to said frame in a first direction substantially towards another positioning plate of the at least two positioning members, and wherein the positioning members are arranged to contact, e.g. compress, the breast when positioned between said positioning members. The known apparatus further comprises a gamma camera positioned to image a volume in the imaging space. The gamma camera comprises:                a collimator provided with at least a first plurality of focused pinholes, each of the pinholes having an individual field of view, the individual fields of view of the first plurality of pinholes defining a common central field of view as the part of space seen by all of the first plurality of pinholes, and        a gamma sensitive detector arranged to receive images from the collimator.The collimator is positioned in a plane substantially parallel to one of the positioning members and is movable in said plane, preferably in orthogonal directions in said plane. The apparatus further comprises a collimator motion device arranged to controllably move the collimator in said plane.        
Although this known apparatus has a relatively high accuracy and resolution, it suffers from the drawback that a relatively large fraction of the images are insufficiently accurate, for example showing an inaccurate location, or direction dependent blurring, of the tumor(s).
This can lead to an undesirably and unnecessarily high number of biopsies, tumor surgeries and breast amputations and also to a higher than necessary number of images being taken, which can cause discomfort or even pain to the patient, in particular to women of whom the breast is being imaged. In addition it can lead to undetected small tumors or parts of tumors in which case no, or insufficient amounts of, tumor tissue will be removed by a surgeon.